NASA has announced that astronaut Scott Kelly will spend a year aboard the International Space Station, the longest any American has spent in space at a single time. Kelly has already spent 180 days in space spread out over 2 shuttle missions and a stint on the ISS which was cut short when his sister-in-law Gabrielle Giffords was shot. Kelly will participate in a study of the effects of space travel on twins with his twin brother, Mark Kelly, also an astronaut, who will remain on Earth. Kelly will join an elite club of four cosmonauts who have spent a year or more in space on a single mission.For more information…